Engine Carburetor Gasket Rebuild Float Choke Repair Kit Model Mfr. Repl. Kit Kit Kit Standard Self-Reliev. CS4, 6 Mikuni 63 757 04-S 63 757 05-S CS8.5 (250cc) Mikuni 63 757 10-S 63 757 08-S CS8.5-12 Mikuni 63 757 01-S 63 757 02-S CH6 Keihin 15 757 09-S 15 757 07-S 15 757 08-S CH/CV11-16 Walbro 12 757 03-S 12 757 02-S 12 757 08-S CH/CV11-16 Nikki 12 757 31-S 12 757 27-S 12 757 30-S 12 757 29-S TH16, 18 Nikki 24 757 20-S 28 757 05-S 28 757 06-S 28 757 08-S CH18-25 Keihin 24 757 03-S 24 757 02-S 24 757 07-S CV17-25 Nikki 24 757 20-S 24 757 18-S 24 757 19-S CH/CV22/23 (674cc) Keihin 24 757 38-S 24 757 46-S 24 757 44-S 24 757 36-S LV675-740 Nikki 24 757 20-S 24 757 18-S 24 757 19-S Engine Carburetor Solenoid Fuel Bowl Accelerator Pump Kit(s) Model Mfr. Kit Repl. Kit Seal & Bush. Diaphragm CS4, 6 Mikuni CS8.5 (250cc) Mikuni CS8.5-12 Mikuni CH6 Keihin CH/CV11-16 Walbro 12 757 33-S 12 757 37-S CH/CV11-16 Nikki 12 757 28-S TH16, 18 Nikki 28 757 07-S CH18-25 Keihin 24 757 01-S 24 757 08-S 24 757 09-S CV17-25 Nikki 24 757 22-S 24 757 21-S CH/CV22/23 (674cc) Keihin 24 757 45-S 24 757 47-S LV675-740 Nikki 28 757 07-S 24 757 21-S Carburetor Service Kits The carburetors for most current production engines are serviced with convenient kits, which include the necessary gaskets, hardware, sealant, etc. The following table lists the service kits by engine model and carburetor manufacturer. For those carburetors where a float kit is not listed, order a rebuild kit which includes the float. PLEASE NOTE: This is a PRELIMINARY copy of the Carburetor Reference Manual.
20
Embed
PLEASE NOTE: This is a PRELIMINARY copy of the ... NOTE: This is a PRELIMINARY copy of the Carburetor Reference Manual. CARBURETOR REFERENCE MANUAL CARBURETORS This reference manual
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Carburetor Service KitsThe carburetors for most current production engines are serviced with convenient kits, whichinclude the necessary gaskets, hardware, sealant, etc. The following table lists the service kitsby engine model and carburetor manufacturer. For those carburetors where a float kit is notlisted, order a rebuild kit which includes the float.
PLEASE NOTE: This is a PRELIMINARY copy of theCarburetor Reference Manual.
CARBURETORREFERENCEMANUAL
CARBURETORS
This reference manual contains information on the various types of carburetors used on Kohler engines. Section 1is a part number cross reference to assist you in selecting the proper replacement carburetor or carburetor kit.Section 2 contains recommended carburetor adjustment procedures for Kohler and Walbro carburetors, andpreliminary needle settings for all carburetors and engine models. Section 3 is a service parts listing.
The cross reference listing will be periodically updated to reflect part number supersessions. All information in thismanual is subject to change. For additional service and repair information see the appropriate service manual foryour model engine.
How To Use This Cross Reference1. Prior to the serial breaks listed, use an original
Kohler adjustable jet carburetor when availablefrom Distributor�s stock.
Where serial breaks are not listed, and the enginewas built with an original Kohler adjustable jetcarburetor, use an original Kohler adjustable jetcarburetor.
2. If an original Kohler adjustable jet carburetor is nolonger available, and the engine serial number isprior to the serial break, order the correspondingWalbro fixed or adjustable jet carburetor kit.
If the engine serial number is at or after the serialbreak, determine the part number of thecarburetor installed on the engine. *The partnumber is stamped on the carburetor mountingflange.)
Section 1Carburetor Cross Reference
3. Locate the carburetor part number (from step 2) ineither the �Walbro Fixed Jet Car� column or�Walbro Adj Jet Carb� column. Use thecorresponding carburetor kit.
4. If a Walbro fixed jet carburetor kit is no longeravailable from Kohler Co./Distributor stock, use thecorresponding Walbro adjustable jet kit.
NOTE: Carburetors listed in the �Walbro Fixed JetCarb� column and �Walbro Adj Jet Carb�column are for reference only. Always orderthe corresponding carburetor kit.
Carburetor kits include a carburetor assembly,gasket and/or linkage.
Kohler engines are equipped with one of two basictypes of carburetors � Kohler or Walbro � fixed main jetor adjustable main jet. This section covers thecarburetor adjustment procedures for all Kohlerengines.
Kohler carburetor adjustments are covered on pages2.1 & 2.2. Walbro carburetor adjustments are coveredon pages 2.3 & 2.4. Preliminary settings for both typecarburetor is on page 2.5.
The carburetor is designed to deliver the correct fuel-to-air mixture to the engine under all operating conditions.The main fuel and low idle fuel needles on adjustablejet carburetors are set at the factory and normally donot need further adjustment. On fixed jet carburetors,the low idle fuel needle is also set at the factory andnormally does not need further adjustment. The mainfuel jet is calibrated and installed at the factory and isnot adjustable*.
*NOTE: Engines operating at altitudes aboveapproximately 1830 m (6000 ft.) may require aspecial �high altitude� main jet.
TroubleshootingIf engine troubles are experienced that appear to befuel system related, check the following areas beforeadjusting the carburetor.
� Make sure the fuel tank is filled with clean, freshgasoline.
� Make sure the fuel tank cap vent is no blocked andthat it is operating properly.
� Make sure fuel is reaching the carburetor. Thisincludes checking the fuel shut-off valve, fuel tankfilter screen, in-line fuel filter, fuel lines, and fuelpump for restrictions or faulty components asnecessary.
� Make sure the air cleaner base and carburetor issecurely fastened to the engine using gaskets ingood condition.
Section 2Carburetor Adjustment
� Make sure the air cleaner element is clean and allair cleaner components are fastened securely.
� Make sure the ignition system, governor system,exhaust system, and throttle and choke controlsare operating properly.
If, after checking the items listed above, starting orengine operation problems exists, it may be necessaryto adjust the carburetor.
NOTE: Carburetor adjustments should be made onlyafter the engine has warmed up.
Kohler Carburetor AdjustmentIn general, turning the adjusting needles in (clockwise)decreases the supply of fuel to the carburetor. Thisgives a leaner fuel-to-air mixture. Turning the adjustingneedles out (counterclockwise) increases the supply offuel to the carburetor. This gives a richer fuel-to-airmixture. Setting the needles midway between the leanand rich positions will usually give the best results.
Adjust the carburetor as follows:1. With the engine stopped, turn the low idle fuel
adjusting needle in (clockwise) until it bottomslightly.
NOTE: The tip of the low idle fuel and main fueladjusting needles are tapered to criticaldimensions. Damage to the needles andthe seats in carburetor body will result ifthe needles are forced.
2. Preliminary Settings: Turn the adjusting needlesout (counterclockwise) from lightly bottomedaccording to the table shown in Figure 2-5.
3. Start the engine and run at half throttle for five toten minutes to warm up. The engine must be warmbefore making final settings steps 4, 5, 6, and 7).
2.1
4. Main Fuel Needle Setting: This adjustment isrequired only for adjustable main jet carburetors. Ifthe carburetor is a fixed main jet type, refer toWalbro adjustment.
Place the throttle into the �fast� position. If possible,place the engine under lead.
Turn the main fuel adjusting needle out(counterclockwise) from the preliminary settinguntil the engine speed decreases (rich). Note theposition of the needle.
Now turn the adjusting needle in (clockwise). Theengine speed may increase, then it will decreaseas the needle is turned in (lean). Note the positionof the needle.
Set the adjusting needle midway between the richand lean settings. See Figure 2-1.
5. Low Idle Speed Setting: Place the throttle controlinto the �idle� or �slow� position. Set the low idlespeed to 1200 RPM* (+ or � 75 RPM) by turningthe low idle speed adjusting screw in or out. Checkthe speed using a tachometer.
*NOTE: The actual low idle speed depends on theapplication. Refer to the equipmentmanufacturer�s instructions for specificlow idle speed settings. Therecommended low idle speed for theBasic Engines is 1200 RPM. To ensurebest results when setting the low idle fuelneedle, the low idle speed must notexceed 1500 RPM.
6. Low Idle Fuel Needle Setting: Place the throttleinto the �idle� or �slow� position.
Turn the low idle fuel adjusting needle out(counterclockwise) from the preliminary settinguntil the engine speed decreases (rich). Note theposition of the needle.
Now turn the adjusting needle in (clockwise). Theengine speed may increase, then it will decreaseas the needle is turned in (lean). Note the positionof the needle.
Set the adjusting needle midway between the richand lean settings. See Figure 2-1.
7. Recheck the low idle speed using a tachometer.Readjust the speed as necessary.
Figure 2-2. Adjusting Needle Locations.
NOTE: The tip of the low idle fuel and main fueladjusting needles are tapered to criticaldimensions. Damage to the needles and theseats in carburetor body will result if theneedles are forced.
Refer to Figure 2-5 for preliminary settings.
1. With the engine stopped, turn the adjustingneedle(s) in (clockwise) until it bottoms lightly.
Lean
Rich
Adjust toMidpoint
Figure 2-1. Optimum Low Idle Fuel Setting.
Walbro Carburetor Adjustment
In general, turning the adjusting needles in (clockwise)decreases the supply fuel to the carburetor. This gives aleaner fuel-to-air mixture. Turning the adjusting needlesout (counterclockwise) increase the supply of fuel to thecarburetor.
Adjust the carburetor as follows, see Figure 2-2 forneedle locations.
Idle Speed ScrewLow IdleFuel Needle
Main FuelNeedle
2.2
2. Preliminary Settings: Turn the adjustingneedle(s) out (counterclockwise) from lightlybottomed according to the table shown in Figure 2-5, or to the rich side of adjustment.
3. Start the engine and run at half throttle for five toten minutes to warm up. The engine must be warmbefore making final settings.
4. Main Fuel Needle Setting: This adjustment isrequired only for adjustable main jet carburetors. Ifthe carburetor is a fixed main jet type, disregardthis setting.
Place the throttle into the �fast� position.
Turn the adjusting needle in (clockwise). Theengine speed may increase, then it will decreaseas the needle is turned in (lean). Note the positionof the needle. Back the needle out approximately1/8 to 1/4 turn. See Figure 2-3 for best main fuelperformance.
Figure 2-3. Optimum Mail Fuel Setting.
5. Low Idle Speed Setting: Place the throttle controlinto the �idle� or �slow� position. Set the low idlespeed to 1200 RPM* (+ or � 75 RPM) by turningthe low idle speed adjusting screw in or out. Checkthe speed using a tachometer.
*NOTE: The actual low idle speed depends on theapplication. Refer to the equipmentmanufacturer�s instructions for specificlow idle speed settings. To ensure bestresults when setting the low idle fuelneedle, the low idle speed must notexceed 1500 RPM.
Back Out Approx.1/8 to 1/4 Turn
Lean Lean
Figure 2-4. Optimum Low Idle Fuel Setting.
6. Low Idle Fuel Needle Setting: Place the throttleinto the �idle� or �slow� position.
Turn the adjusting needle in (clockwise). Theengine speed may increase, then it will decreaseas the needle is turned in (lean). Note the positionof the needle.
Back the needle out approximately 1/8 to 1/4 turn.See Figure 2-4 for best low idle fuel performance.
Back Out Approx.1/8 to 1/4 Turn
Lean Lean
2.3
2.4
Preliminary SettingsK-Series Models
WalbroKohler Adjustable Jet Fixed Jet Walbro Adjustable JetLow Idle High Idle Low Idle Low Idle Main Fuel
Kohler Adjustable Jet Fixed Jet Walbro Adjustable JetLow Idle High Idle Low Idle Low Idle Main Fuel
C5 NOT APPL NOT APPL 1 turn NOT APPL NOT APPLCV12.5 NOT APPL NOT APPL 1 turn NOT APPL NOT APPL
Figure 2-5.
Section 3SERVICE PARTS LISTING
This section contains indexed illustrations and complete part number breakdowns for the Kohler adjustable andWalbro fixed/adjustable carburetors.
The Kohler carburetors are covered on pages 3.2 � 3.5. 1/2� Walbro carburetors are covered on pages 3.6 � 3.7.1� Walbro carburetors are covered on pages 3.8 � 3.11.
Here is a listing for quick reference of all fixed main jets and high altitude jet kits and jet size.